The Ganges River Dolphin (Platanista gangetica gangetica) is a fascinating freshwater creature and, sadly, an endangered species.
They are known as the “Tiger of the Ganges” for the role it plays as a top predator, and because it is an ecosystem indicator species – much like a tiger is in a forest.
It is legally protected in all countries within which it is found. Both Indus river dolphins and Ganges river dolphins are considered to be living fossils, as they are the most ancient dolphin species still alive
- Common names: South Asian river dolphin, Ganga dolphin, Gangetic dolphin.
- Names in local languages: Reminiscent of the noise the dolphin makes when it breathes, such as susu, soos, shushuk, socho, shus, and suongsu.
These remarkable mammals hold a special place in India, designated as the country’s national aquatic animal in 2009.
Biological features
- Ganges river dolphins are usually a grey or light brown colour, but may also have a pinkish tone to the belly.
- The dolphins have an elongated snout, a steep forehead, and flexible necks with unfused vertebrae which permit them to turn their heads from side to side.
- They have long, sharp teeth which are visible even when the mouth is closed.
- This species is functionally blind and therefore relies heavily on echolocation to navigate and hunt.
What is Echolocation or Seeing with Sound?
- One of the most remarkable adaptations of the Gangetic dolphin is their ability to navigate and hunt despite being blind.
- They rely on a biological sonar system called echolocation.
- By emitting high-frequency clicks and interpreting the echoes that bounce back, they can form a mental picture of their surroundings, locate prey, and avoid obstacles.
Habitat
Fragile Freshwater Residents
- Unlike their saltwater cousins, Gangetic dolphins thrive solely in freshwater environments.
- Their ideal habitat consists of freshwater rivers with a depth of 5 to 8 feet, deeper sections of the river.
- This specific depth range allows them to navigate and hunt effectively.
- They prefer eddies around islands, river bends, and confluences which are often also the places where people prefer to fish.
Now dams and barrages restrict dolphin movement.
But in the past during the monsoon season, the dolphins would have moved upstream into smaller rivers, and then back downstream to larger river channels in the low-water winter season.
Distribution of Ganges River Dolphin
- Gangetic dolphins can be found in India, Bangladesh, and Nepal.
- In over 10,000 km of the Ganges-Brahmaputra-Meghna, and the Sangu-Karnaphuli River systems, a vital part of these countries’ freshwater ecosystems.
Threats to Ganges River Dolphin
The major threats to the Ganges river dolphin include:
- Water-related infrastructure such as dams, barrages, diversions, and embankments
- This causes flow regulation and habitat fragmentation, reducing population connectivity and isolating animals in river sections.
- Mortality from entanglement in fishing nets.
- Hunting of dolphins for oil and meat.
- Pollution from domestic, industrial, and agricultural sources: heavy metals.
- Disturbance from human activities including boat traffic, dredging, and underwater noise.
- They also affect river habitats by reducing water availability and habitat quality and blocking passage for migratory fish.
- These factors disrupt their delicate ecosystem and make it difficult for them to survive and thrive.
- River cetaceans, including the Ganges river dolphin, are considered to be indicators of river health.
Conservation Efforts
While the Gangetic dolphin faces significant threats, there are ongoing efforts to ensure its survival.
Conservation Status
- Listed as Endangered on the IUCN Red List since 1996
- Listed in Schedule I of the Indian Wildlife Protection Act (1972)
- Convention on International Trade in Endangered Species (CITES): Appendix I (most endangered)
National Dolphin Research Centre (NDRC)
- Established in 2024 in Patna, India, near the Ganga River.
- It researches Gangetic dolphin behavior, survival skills, food habits, and causes of mortality.
- Aims to develop effective conservation strategies based on research findings.
- Includes training for fishermen on sustainable practices to minimize accidental entanglement.
